Distal and lateral subungual onychomycosis of the finger nail in a neonate: a rare case

Onychomycosis is a common nail plate infection caused by dermatophytes, non-dermatophytic molds, and yeasts. The prevalence of this condition is low in children as compared to adults and even rarer in the newborn [1]. Nevertheless, this diagnosis cannot be excluded in children, and neonates are presenting with nail plate disorders. Candida onychomycosis, most frequently caused by Candida albicans, rather than any other Candida species, often clinically presents as paronychia, onycholysis [2] and onychorrhexis. Onycholysis as a pathological entity in children is more commonly caused by dermatophytes and usually present with a single toenail infection having features of disto-lateral subungual onychomycosis [3]. Distal lateral subungual onychomycosis due to Candida is extremely uncommon in the neonates. We here describe a case of dorsal lateral onychomycosis of a fingernail due to C. albicans in a newborn baby. This is the first ever report of neonatal onychomycosis in Nepal, and the case is presented for its extreme rarity.

The parents brought a 28-day-old male child to the Dermatology outpatient department of Manipal Teaching Hospital, Pokhara, Nepal with the complaints of yellowish discoloration of the nail with slight swelling of the upper part of the middle finger of the left hand for one week. Mother reported that the baby had been suckling this finger since birth. The baby was well two weeks back when he developed slight yellowish discoloration of the middle finger of the left hand. The stain spread proximally with increasing thickness of the nail. There was no family history of fungal infections, psoriasis, lichen planus, Darrier’s disease, or yellow nail syndrome. There were no other risk factors suggestive of HIV infection in the parents. The baby was delivered at 39 weeks of gestational age via normal vaginal delivery and weighed 3250 g. There was no history of perinatal hypoxia. His developmental milestones were appropriate for his age.

On examination, the physical activities of baby were as per his age. There was noticeable yellowish discoloration of the nail of the middle finger of the left hand distally with yellowish subungal hyperkeratotic debris. Pitting or whitish deposits on the nail were not evident. Examination of the skin revealed no lesions suggestive of fungal infections, psoriasis, lichen planus or Darrier’s disease. Scalp hairs were healthy. Oral and genital surfaces were normal without any lesions suggestive of mucosal candidiasis. Systemic examination was within normal limits. It was provisionally diagnosed as onychomycosis. The nail was trimmed, and parents were counselled to come for follow-up every month, keeping in view that the condition may be self-limiting. However, at two months follow up, increased discoloration and thickness of the nail without the involvement of glabrous skin was observed. Nail specimens (nail clippings) and oral swabs were sent for laboratory diagnosis.

Onychomycosis is common in adults, with an increasing prevalence with age due to reduced nail growth accompanied by an increase in nail plate thickness [5‐7]. Onychomycoses commonly affects toenails and is rarely seen in children. The rarity of this condition in pediatric patients has been attributed to the differences in nail plate structure, less exposure to trauma, and faster linear nail growth [5].

Etiological agents of onychomycosis include the dermatophytes Trichophyton rubrum and Trichophyton mentagrophytes [7, 8]. The role of Candida species in onychomycosis has also been established but is still primarily considered to cause onychomycosis secondary to paronychial disease or peripheral vascular disease [9‐11]. According to earlier studies, out of all Candida species, C. albicans accounted for 57–87% of the infections [10, 12]. However, C. albicans causing nail infection in children and neonates are far less commonly encountered. The case is therefore reported for its rarity.

The present case was a 28-day-old healthy neonate with no predisposing condition in mother or neonate [13]. The mother was immunocompetent with no history of indwelling catheters. Neither the mother nor the neonate received broad-spectrum antibiotics or parenteral alimentation. Neonatal onychomycosis has been sparsely reported, and mainly ascribed to be due to Candida tropicalis, Candida albicans, Candida parapsilosis and Trichophyton rubrum [14]. The age range of reported cases with onychomycosis is 35 days to 10 weeks [14, 15]. Chun et al. [16] reported onychomycosis (an isolated lesion of the nail plate without the involvement of the glabrous skin caused by C. tropicalis) in a 107-day old infant. Our case had a clinical presentation similar to that documented by Chun et al. [16], except for the younger age. In spite of the discrepancies as mentioned above in the clinical presentation and pathology, Candida could be accounted as an important cause of onychomycosis in the pediatric age group. In a survey of 46 cases of onychomycosis in children, Candida was placed as the second causative agent of onychomycosis, next to dermatophytes [17]. Hay et al. [9] observed onychomycoses in subjects following chronic mucocutaneous candidiasis and chronic paronychia. Carvalho VO, et al. [1] documented childhood onychomycosis due to Fusarium oxysporum, which was acquired in-utero. It was a progressing, ascending infection in an HIV positive mother involving the placenta and nail as proved by molecular methods. Congenital candidiasis, acquired transplacentally, as shown earlier [1], might present with skin rash, but also could affect skin appendages as reported in the past [18]. The present neonatal distal lateral subungual onychomycosis without any predisposing conditions either in the baby or the mother is a rarity.

Candida onychomycosis in infants and neonates without any predisposition is rare. Sanchez-Schmidt et al. [19] have reported nail changes suggestive of onychomycoses appearing between 2 and 6 weeks of life without any signs of immunosuppression in any of their cases. Histopathological shreds of evidence, such as distal lateral subungual lesions with onycholysis, as seen in our case are similar to those showed by Hay et al. [9]. He noticed three patterns of nail diseases due to Candida: total dystrophic onychomycosis, mostly seen in chronic mucocutaneous candidiasis; proximal and lateral nail dystrophy, secondary to chronic paronychia; and distal and lateral nail dystrophy, associated with onycholysis, sloughing of the nail with peripheral vascular disease, and finger and toenail abnormalities.

In this case, the clinical diagnosis of onychomycosis was made during the first visit itself. Thus the patient was advised to come for follow up with nail trimming, without any antifungal use, with the assumption that there would be a spontaneous resolution in a few months, because of the faster linear growth of the nail in children.

We have reported a case of onychomycosis caused by C. albicans in a neonate without any evidence of a compromised immune system in the mother or the baby. Accurate identification of the causative agent and timely initiation of antifungal therapy led to complete recovery. To the best of our knowledge, this is the first case report of onychomycosis due to C. albicans at such a young age. Oral colonization with pathogenic yeasts and finger suckling could be risk factors for neonatal onychomycosis.